1. Technical Field
The present disclosure relates generally to nuclear magnetic resonance (NMR) and, more specifically, to techniques for processing of NMR echo data.
2. Background Information
This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the subject matter described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, not as admissions of prior art.
Logging tools may be used in wellbores to make, for example, formation evaluation measurements to infer properties of the formations surrounding the borehole and/or the fluids in the formations. Common logging tools include electromagnetic tools, nuclear tools, acoustic tools, and nuclear magnetic resonance (NMR) tools, though various other types of tools for evaluating formation properties are also available.
Early logging tools were run into a wellbore on a wireline cable after the wellbore had been drilled. Modern versions of such wireline tools are still used. However, as the demand for (e.g., real-time) information while drilling a borehole continued to increase, measurement-while-drilling (MWD) tools and logging-while-drilling (LWD) tools have since been developed. MWD tools typically provide drilling parameter information such as weight on the bit, torque, temperature, pressure, direction, and inclination. LWD tools typically provide formation evaluation measurements such as resistivity, porosity, NMR distributions, and so forth. MWD and LWD tools often have characteristics common to wireline tools (e.g., transmitting and receiving antennas, sensors, etc.), but MWD and LWD tools may be designed and constructed to endure and operate in the environment of drilling.
NMR tools used in well logging generally measure, among other things, relaxation times, such as longitudinal relaxation times (T1) or transverse relaxation times (T2), of formation fluids, which may range from a fraction of a millisecond to several seconds. NMR data may be used to determine properties of a zone of interest, e.g., substance thereof.